We are trying to get WCF and Java talking to each other using SAML tokens issued from an STS. Despite the fact that both sides are compliant with the standards, WS-Security, WS-
We have successfully tested Rampart for WS-Trust scenarios with WCF both at the client and server ends.
BTW Rampart doesn't have WS-Federation scenarios supported yet and your security policy could be related to it. [FYI - WS-Federation will be available with Rampart mid next year].
If you can please attach the security policies we can have a close look..